Five snowboarders have been killed in an avalanche in Colorado, according to authorities.

The Clear Creek County sheriff, Don Krueger, said in a statement that six snowboarders were caught in the slide, which took place on Saturday. The condition of the lone survivor was not released, and it was unclear if the victims were still buried.

Colorado Avalanche Information Center forecaster Spencer Logan said there had been weak layers in Colorado's snowpack since early January.

"Our last series of storms made them more active again," he said.

US avalanche deaths climbed steeply around 1990 to an average of about 24 a year as new equipment became available for backcountry travel. Until then, avalanches rarely claimed more than a handful of lives each season in records going back to 1950.